1. Field of the Invention
The present invention generally relates to a magnetic video reproducing apparatus having a still picture reproducing function. More specifically, the present invention relates to an improvement in a magnetic video reproducing apparatus employing a rotational plural-head system, a helical scan system and an azimuth system and having a still picture reproducing function.
2. Description of the Prior Art
A magnetic video tape recording/reproducing apparatus for home use so far proposed and put into practical use typically employs a rotational two-head system, a helical scan system and an azimuth system. By a rotational two-head system is typically meant a system in which two video heads are provided at the directly opposite positions on the circumference of a rotating drum spaced apart by 180.degree. from each other. By a helical scan system is typically meant a system in which a magnetic tape is made to travel in an oblique direction with respect to the rotational direction of the video heads. By an azimuth system is typically meant a system in which the gap directions of the above described two heads are each afforded a different angle so that the gap corresponding directions on the recorded tracks recorded by the above described two heads on a magnetic tape may be different and hence may intersect each other. The above described rotational two-head system, helical scan system and azimuth system have been fully described in, for example, U.S. Pat. No. 3,925,810 issued Dec. 9, 1975 to Yoshio Ishigaki et al; U.S. Pat. No. 3,812,523 issued May 21, 1974 to Hisaaki Narahara; U.S. Pat. No. 4,012,771 issued Mar. 15, 1977 to Yoshio Ishigaki et al; U.S. Pat. No. 3,918,085 issued Nov. 4, 1975 to Toshihiko Numakura et al; and U.S. Pat. No. 4,079,412 issued Mar. 14, 1978 to Yoshiteru Kosaka. Since the above described three systems constitute the background of the present invention, the above referenced U.S. patents are herein incorporated by reference thereto.
A still picture reproducing function for use in such a magnetic video tape recording/reproducing apparatus has also been proposed and put into practical use. One conventional approach to shift from an ordinary reproducing mode to a still picture reproducing mode in such magnetic video reproducing apparatus is to obtain some signal from a magnetic tape such as to read a control signal recorded at a position separate from that for a picture signal and to stop a capstan shaft for feeding a magnetic tape in a longitudinal direction within a predetermined period of time. Another conventional approach to shift from an ordinary reproducing mode to a still picture reproducing mode in such a magnetic video tape recording/reproducing apparatus is to confirm that a noise band on the screen has come off the position corresponding to the vertical blanking period to pulse drive, one or several times, a capstan shaft driving motor by a predetermined width, so that a noise band may be expelled from the screen. However, the first mentioned approach involves a disadvantage in that the characteristics of castan shaft driving motors are not uniform and in addition the position of a control signal becomes different depending on the characteristic of a magnetic video tape recording/reproducing apparatuses, so that it is not assuredly guaranteed that always a noiseless still picture is attained when a tape is stopped on the occasion of a still picture reproducing mode. On the other hand, the second mentioned approach also involves a disadvantage in that more time is required to remove a noise band from the screen, which makes viewers worry about the existence of a noise band.